Until motherboards with chipsets able to use the new DDR RAM, Intel Pentium 4 processors could only use Rambus RAM, which runs at an effective speed of 400MHz, and is comparatively still very expensive compared to standard PC 100 and PC 133 SDRAM, and PC 1600 and PC 2100 DDR RAM. - See below for the news that has just come out that VIA has developed a chipset that supports DDR SDRAM. AMD Athlon processors can run on motherboards that use PC 1600 and PC 2100 DDR RAM. AMD Duron processors
run on a 100MHz system bus that can only use the PC 1600 DDR RAM. PC 2100 DDR RAM runs on a 133MHz system bus. - More on this further down the article.
Below is a table that provides some interesting information about the differences between recent types of RAM technologie
You can use some of the easy tools to find your exact DDR or DDR2 Memory Upgrades for your Desktop, Laptop or Servers. Use the Memory Selector to find compatible DDR or DDR2 Memory Upgrades, or the all new system scanner tool to scan your system to find exact matching DDR RAM. If you need more help use the Live Chat Support
DDR SDRAM for desktop computers DIMMs have 184 pins (as opposed to 168 pins on SDRAM, or 240 pins on DDR2 SDRAM), and can be differentiated from SDRAM DIMMs by the number of notches (DDR SDRAM has one, SDRAM has two). DDR for notebook computers SO-DIMMs have 200 pins which is the same number of pins as DDR2 SO-DIMMs. These two specifications are notched very similarly and care must be taken during insertion when you are unsure of a correct match
DDR2 introduces some new features which allow it to ramp up to much higher speeds (with correspondingly higher bandwidth) and higher memory densities, all the while using less power. DDR2 memory uses a new form factor, a 240 pin DIMM (Dual Inline Memory Module) which is *not* compatible with current DDR memory slots. Upcoming chipsets by Intel and other manufacturers will support DDR2 specifically, and are not backwards compatible.